NEWARK -- A former senior policy advisor for U.S. Sen. Robert Menendez said he wasn't trying to conceal what he was doing when he used his personal email account to discuss visa applications sought by Florida eye doctor Salomon Melgen.

On the witness stand in U.S. District Judge William H. Walls' fourth-floor courtroom Tuesday morning, Mark Lopes told defense attorney Raymond M. Brown that was no "nefarious intent," in Brown's words, behind the use of his private email account.

Menendez, D-N.J., and Melgen, both 63, are on trial in U.S. District Court on an indictment accusing the men of swapping government favors for private plane flights, luxury hotel stays and $750,000 in financial contributions.

Lopes testified Monday that he was part of the senator's intervention in the 2008 visa applications of two of the girlfriends, Juliana Lopes Leite and Rosiell Polanco, and that of Polanco's sister, Korall.

After the visas for the Polanco sisters were approved -- after initially being denied -- Lopes used his personal email account to write to Danny O'Brien, then the senator's chief of staff.

"In my view, this is only due to RM," Lopes wrote, referring to the senator.

A year after the visa applications, Lopes said, he met Melgen in Valencia, Spain at a meeting with Menendez and international business leaders from Spain, the U.S. and other countries.

Lopes said that at the time he met Melgen, he did not reemember he had helped with the women's visa applications, as such visa interventions were -- in Brown's words -- a "sufficiently routine" part of his duties.

The former staffer on Monday denied there was anything improper about the office's support for the visa applications, and that other staff members were working on other visa issues during that time.

On redirect, government prosecutor J.P. Cooney asked whether an initial letter Menendez's office sent to the consul general in the Dominican Republic, where the Polanco sisters lived, was successful in securing their approval.

"Apparently not, no," Lopes said.

Only after Menendez asked Lopes to call the U.S. ambassador to the country -- the consul general's boss, "for practical purposes" -- did the women clear the approval process, he testified.

The judge would not let Cooney ask Lopes whether he was aware of the senator's flights on Melgen's private plane, ruling it was "immaterial as to whether he was aware or not aware."

The trial before Walls was originally expected to last six to eight weeks, but a new trial schedule approved by the judge Tuesday has the proceedings slated to continue through Thanksgiving.

"I'm surprised the way this case is going you didn't carry it through Martin Luther King's Day," Walls told prosecutors.